//==========================================================================
// Copyright (c) 2000-2008,  Elastos, Inc.  All Rights Reserved.
//==========================================================================
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: erase.cpp,v 1.5 2006/05/16 14:13:32 shijun Exp $
 *
 */

#include <linux/mtd/mtd.h>
#include <linux/crc32.h>
#include "linux/slab.h"
#include "jffs2_misc.h"
#include "linux/sched.h"
#include "nodelist.h"

struct erase_priv_struct
{
    struct jffs2_eraseblock *jeb;
    struct jffs2_sb_info *c;
};

#ifndef __ELAOS
static void jffs2_erase_callback(struct erase_info *);
#endif
static void jffs2_erase_failed(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb, uint32_t bad_offset);
static void jffs2_erase_succeeded(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb);
static void jffs2_free_all_node_refs(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb);
static void jffs2_mark_erased_block(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb);

static void jffs2_erase_block(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb)
{
    int ret;
    uint32_t bad_offset;
#ifdef __ELAOS

    ret = jffs2_flash_erase(c, jeb);
    if (!ret) {
        jffs2_erase_succeeded(c, jeb);
        return;
    }
    bad_offset = jeb->offset;
#else /* Linux */

    struct erase_info *instr;

    D1(printk(KERN_DEBUG "jffs2_erase_block(): erase block %#08x (range %#08x-%#08x)\n",
              jeb->offset, jeb->offset, jeb->offset + c->sector_size));
    instr = kmalloc(sizeof(struct erase_info) + sizeof(struct erase_priv_struct), GFP_KERNEL);
    if (!instr) {
        printk(KERN_WARNING "kmalloc for struct erase_info in jffs2_erase_block failed. Refiling block for later\n");
        spin_lock(&c->erase_completion_lock);
        list_del(&jeb->list);
        list_add(&jeb->list, &c->erase_pending_list);
        c->erasing_size -= c->sector_size;
        c->dirty_size += c->sector_size;
        jeb->dirty_size = c->sector_size;
        spin_unlock(&c->erase_completion_lock);
        return;
    }

    memset(instr, 0, sizeof(*instr));

    instr->mtd = c->mtd;
    instr->addr = jeb->offset;
    instr->len = c->sector_size;
    instr->callback = jffs2_erase_callback;
    instr->priv = (unsigned long)(&instr[1]);
    instr->fail_addr = 0xffffffff;

    ((struct erase_priv_struct *)instr->priv)->jeb = jeb;
    ((struct erase_priv_struct *)instr->priv)->c = c;

    ret = c->mtd->erase(c->mtd, instr);
    if (!ret)
        return;

    bad_offset = instr->fail_addr;
    kfree(instr);
#endif /* __ELAOS */

    if (ret == ENOMEM || ret == EAGAIN) {
        /* Erase failed immediately. Refile it on the list */
        D1(printk(KERN_DEBUG "Erase at 0x%08x failed: %d. Refiling on erase_pending_list\n", jeb->offset, ret));
        spin_lock(&c->erase_completion_lock);
        list_del(&jeb->list);
        list_add(&jeb->list, &c->erase_pending_list);
        c->erasing_size -= c->sector_size;
        c->dirty_size += c->sector_size;
        jeb->dirty_size = c->sector_size;
        spin_unlock(&c->erase_completion_lock);
        return;
    }

    if (ret == EROFS)
        printk(KERN_WARNING "Erase at 0x%08x failed immediately: EROFS. Is the sector locked?\n", jeb->offset);
    else
        printk(KERN_WARNING "Erase at 0x%08x failed immediately: errno %d\n", jeb->offset, ret);

    jffs2_erase_failed(c, jeb, bad_offset);
}

void jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count)
{
    struct jffs2_eraseblock *jeb;

    WaitResult wr;
    down(&c->erase_free_sem, &wr);

    spin_lock(&c->erase_completion_lock);

    while (!list_empty(&c->erase_complete_list)
            || !list_empty(&c->erase_pending_list)) {

        if (!list_empty(&c->erase_complete_list)) {
            jeb = list_entry(c->erase_complete_list.next, struct jffs2_eraseblock, list);
            list_del(&jeb->list);
            spin_unlock(&c->erase_completion_lock);
            jffs2_mark_erased_block(c, jeb);

            if (!--count) {
                D1(printk(KERN_DEBUG "Count reached. jffs2_erase_pending_blocks leaving\n"));
                goto done;
            }
        }
        else if (!list_empty(&c->erase_pending_list)) {
            jeb = list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list);
            D1(printk(KERN_DEBUG "Starting erase of pending block 0x%08x\n", jeb->offset));
            list_del(&jeb->list);
            c->erasing_size += c->sector_size;
            c->wasted_size -= jeb->wasted_size;
            c->free_size -= jeb->free_size;
            c->used_size -= jeb->used_size;
            c->dirty_size -= jeb->dirty_size;
            jeb->wasted_size = jeb->used_size = jeb->dirty_size = jeb->free_size = 0;
            jffs2_free_all_node_refs(c, jeb);
            list_add(&jeb->list, &c->erasing_list);
            spin_unlock(&c->erase_completion_lock);

            jffs2_erase_block(c, jeb);
        }
        else {
            BUG();
        }

        /* Be nice */
        cond_resched();
        spin_lock(&c->erase_completion_lock);
    }

    spin_unlock(&c->erase_completion_lock);
done:
    D1(printk(KERN_DEBUG "jffs2_erase_pending_blocks completed\n"));

    up(&c->erase_free_sem);
}

static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
    D1(printk(KERN_DEBUG "Erase completed successfully at 0x%08x\n", jeb->offset));
    spin_lock(&c->erase_completion_lock);
    list_del(&jeb->list);
    list_add_tail(&jeb->list, &c->erase_complete_list);
    spin_unlock(&c->erase_completion_lock);
    /* Ensure that kupdated calls us again to mark them clean */
    jffs2_erase_pending_trigger(c);
}

static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
{
    /* For NAND, if the failure did not occur at the device level for a
       specific physical page, don't bother updating the bad block table. */
    if (jffs2_cleanmarker_oob(c) && (bad_offset != 0xffffffff)) {
        /* We had a device-level failure to erase.  Let's see if we've
           failed too many times. */
        if (!jffs2_write_nand_badblock(c, jeb, bad_offset)) {
            /* We'd like to give this block another try. */
            spin_lock(&c->erase_completion_lock);
            list_del(&jeb->list);
            list_add(&jeb->list, &c->erase_pending_list);
            c->erasing_size -= c->sector_size;
            c->dirty_size += c->sector_size;
            jeb->dirty_size = c->sector_size;
            spin_unlock(&c->erase_completion_lock);
            return;
        }
    }

    spin_lock(&c->erase_completion_lock);
    c->erasing_size -= c->sector_size;
    c->bad_size += c->sector_size;
    list_del(&jeb->list);
    list_add(&jeb->list, &c->bad_list);
    c->nr_erasing_blocks--;
    spin_unlock(&c->erase_completion_lock);
    wake_up(&c->erase_wait);
}

#ifndef __ELAOS
static void jffs2_erase_callback(struct erase_info *instr)
{
    struct erase_priv_struct *priv = (void *)instr->priv;

    if (instr->state != MTD_ERASE_DONE) {
        printk(KERN_WARNING "Erase at 0x%08x finished, but state != MTD_ERASE_DONE. State is 0x%x instead.\n", instr->addr, instr->state);
        jffs2_erase_failed(priv->c, priv->jeb, instr->fail_addr);
    }
    else {
        jffs2_erase_succeeded(priv->c, priv->jeb);
    }
    kfree(instr);
}
#endif /* !__ELAOS */

/* Hmmm. Maybe we should accept the extra space it takes and make
   this a standard doubly-linked list? */
static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
                struct jffs2_raw_node_ref *ref, struct jffs2_eraseblock *jeb)
{
    struct jffs2_inode_cache *ic = NULL;
    struct jffs2_raw_node_ref **prev;

    prev = &ref->next_in_ino;

    /* Walk the inode's list once, removing any nodes from this eraseblock */
    while (1) {
        if (!(*prev)->next_in_ino) {
            /* We're looking at the jffs2_inode_cache, which is
               at the end of the linked list. Stash it and continue
               from the beginning of the list */
            ic = (struct jffs2_inode_cache *)(*prev);
            prev = &ic->nodes;
            continue;
        }

        if (SECTOR_ADDR((*prev)->flash_offset) == jeb->offset) {
            /* It's in the block we're erasing */
            struct jffs2_raw_node_ref *thisOne;

            thisOne = *prev;
            *prev = thisOne->next_in_ino;
            thisOne->next_in_ino = NULL;

            if (thisOne == ref)
                break;

            continue;
        }
        /* Not to be deleted. Skip */
        prev = &((*prev)->next_in_ino);
    }

    /* PARANOIA */
    if (!ic) {
        printk(KERN_WARNING "inode_cache not found in remove_node_refs()!!\n");
        return;
    }

    D1(printk(KERN_DEBUG "Removed nodes in range 0x%08x-0x%08x from ino #%u\n",
              jeb->offset, jeb->offset + c->sector_size, ic->ino));

    D2({
           int i=0;
           struct jffs2_raw_node_ref *thisOne;
           printk(KERN_DEBUG "After remove_node_refs_from_ino_list: \n" KERN_DEBUG);

           thisOne = ic->nodes;

           while(thisOne) {
           printk( "0x%08x(%d)->", ref_offset(thisOne), ref_flags(thisOne))
               ;
               if (++i == 5) {
                   printk("\n" KERN_DEBUG);
                   i=0;
               }
               thisOne = thisOne->next_in_ino;
           }
           printk("\n");
       }
    );

    if (ic->nodes == (void *)ic && ic->nlink == 0)
        jffs2_del_ino_cache(c, ic);
}

static void jffs2_free_all_node_refs(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb)
{
    struct jffs2_raw_node_ref *ref;
    D1(printk(KERN_DEBUG "Freeing all node refs for eraseblock offset 0x%08x\n",
                    jeb->offset));
    while (jeb->first_node) {
        ref = jeb->first_node;
        jeb->first_node = ref->next_phys;

        /* Remove from the inode-list */
        if (ref->next_in_ino)
            jffs2_remove_node_refs_from_ino_list(c, ref, jeb);
        /* else it was a non-inode node or already removed, so don't bother */

        jffs2_free_raw_node_ref(ref);
    }
    jeb->last_node = NULL;
}

static int jffs2_block_check_erase(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb, uint32_t *bad_offset)
{
    void *ebuf;
    uint32_t ofs;
    size_t retlen;
    int ret = EIO;

    ebuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
    if (!ebuf) {
        printk(KERN_WARNING "Failed to allocate page buffer for verifying erase at"
                        " 0x%08x. Refiling\n", jeb->offset);
        return EAGAIN;
    }

    D1(printk(KERN_DEBUG "Verifying erase at 0x%08x\n", jeb->offset));

    for (ofs = jeb->offset; ofs < jeb->offset + c->sector_size;) {
        uint32_t readlen = min((uint32_t)PAGE_SIZE,
                        jeb->offset + c->sector_size - ofs);
        uint32_t i;

        *bad_offset = ofs;

        ret = jffs2_flash_read(c, ofs, readlen, &retlen, (unsigned char *)ebuf);
        if (ret) {
            printk(KERN_WARNING "Read of newly-erased block at 0x%08x failed: %d."
                            " Putting on bad_list\n", ofs, ret);
            goto fail;
        }
        if (retlen != readlen) {
            printk(KERN_WARNING "Short read from newly-erased block at 0x%08x. "
                            "Wanted %d, got %zd\n", ofs, readlen, retlen);
            goto fail;
        }
        for (i = 0; i < readlen; i += sizeof(unsigned long)) {
            /* It's OK. We know it's properly aligned */
            unsigned long *datum = (unsigned long *)((char *)ebuf + i);
            if (*datum + 1) {
                *bad_offset += i;
                printk(KERN_WARNING "Newly-erased block contained word 0x%lx at "
                                "offset 0x%08x\n", *datum, *bad_offset);
                goto fail;
            }
        }
        ofs += readlen;
        cond_resched();
    }
    ret = 0;
fail:
    kfree(ebuf);
    return ret;
}

static void jffs2_mark_erased_block(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb)
{
    struct jffs2_raw_node_ref *marker_ref = NULL;
    size_t retlen;
    int ret;
    uint32_t bad_offset;

    switch (jffs2_block_check_erase(c, jeb, &bad_offset)) {
        case EAGAIN:
            goto refile;
        case EIO:
            goto filebad;
    }

    /* Write the erase complete marker */
    D1(printk(KERN_DEBUG "Writing erased marker to block at 0x%08x\n",
                    jeb->offset));
    bad_offset = jeb->offset;

    /* Cleanmarker in oob area or no cleanmarker at all ? */
    if (jffs2_cleanmarker_oob(c) || c->cleanmarker_size == 0) {

        if (jffs2_cleanmarker_oob(c)) {
            if (jffs2_write_nand_cleanmarker(c, jeb))
                goto filebad;
        }

        jeb->first_node = jeb->last_node = NULL;
        jeb->free_size = c->sector_size;
        jeb->used_size = 0;
        jeb->dirty_size = 0;
        jeb->wasted_size = 0;
    }
    else {

        struct kvec vecs[1];
        struct jffs2_unknown_node marker;
        marker.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
        marker.nodetype = cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER);
        marker.totlen = cpu_to_je32(c->cleanmarker_size);

        marker_ref = jffs2_alloc_raw_node_ref();
        if (!marker_ref) {
            printk(KERN_WARNING "Failed to allocate raw node ref for"
                            " clean marker. Refiling\n");
            goto refile;
        }

        marker.hdr_crc = cpu_to_je32(crc32(0, &marker,
                        sizeof(struct jffs2_unknown_node)-4));

        vecs[0].iov_base = (char *) &marker;
        vecs[0].iov_len = sizeof(marker);
        ret = jffs2_flash_direct_writev(c, vecs, 1, jeb->offset, &retlen);

        if (ret || retlen != sizeof(marker)) {
            if (ret)
                printk(KERN_WARNING "Write clean marker to block at 0x%08x "
                                "failed: %d\n",
                       jeb->offset, ret);
            else
                printk(KERN_WARNING "Short write to newly-erased block at"
                                " 0x%08x: Wanted %zd, got %zd\n",
                       jeb->offset, sizeof(marker), retlen);

            jffs2_free_raw_node_ref(marker_ref);
            goto filebad;
        }

        marker_ref->next_in_ino = NULL;
        marker_ref->next_phys = NULL;
        marker_ref->flash_offset = jeb->offset | REF_NORMAL;
        marker_ref->__totlen = c->cleanmarker_size;

        jeb->first_node = jeb->last_node = marker_ref;

        jeb->free_size = c->sector_size - c->cleanmarker_size;
        jeb->used_size = c->cleanmarker_size;
        jeb->dirty_size = 0;
        jeb->wasted_size = 0;
    }

    spin_lock(&c->erase_completion_lock);
    c->erasing_size -= c->sector_size;
    c->free_size += jeb->free_size;
    c->used_size += jeb->used_size;

    jffs2_dbg_acct_sanity_check_nolock(c,jeb);
    jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

    list_add_tail(&jeb->list, &c->free_list);
    c->nr_erasing_blocks--;
    c->nr_free_blocks++;
    spin_unlock(&c->erase_completion_lock);
    wake_up(&c->erase_wait);
    return;

filebad:
    spin_lock(&c->erase_completion_lock);
    /* Stick it on a list (any list) so erase_failed can take it
       right off again.  Silly, but shouldn't happen often. */
    list_add(&jeb->list, &c->erasing_list);
    spin_unlock(&c->erase_completion_lock);
    jffs2_erase_failed(c, jeb, bad_offset);
    return;

refile:
    /* Stick it back on the list from whence it came and come back later */
    jffs2_erase_pending_trigger(c);
    spin_lock(&c->erase_completion_lock);
    list_add(&jeb->list, &c->erase_complete_list);
    spin_unlock(&c->erase_completion_lock);
    return;
}
